Last year, in June, I upgraded from my D-90 to a D-7500 camera. The reason for the upgrade was that the D-7500 is better in filming, can take time-lapses and is faster. I wanted to stick with the Nikon brand as I already had five lenses, filters, etc.
Since day one I had trouble taking pictures on the Automatic-settings: Every pictures is too dark and under-exposed. Yes, I know, before you shout to me:"You should only take pictures in manual mode!", I want to explain that I'm not a professional photographer. I do a lot of traveling and most of the pictures are taken on the spur of the moment where I don't have time to go through all the settings. Please, accept for what I do. My D-90 performed flawless taking pictures on automatic mode with the same lenses. I also like the idea of having one zoom-lens instead of swapping lenses during inclement weather conditions.

I sent off my camera twice to a Nikon repair center here in Melbourne and twice their response was telling me there's nothing wrong with the camera. The first time I sent the camera was without the lenses. The second time with my lenses. On the second time they told me that the Tamron (18-270 f:3.5-6.3) lens was to blame. I ordered a new lens, a Tamron AF 18-400 F/3.5-6.3 DI II VC HLD with Nikon mount. When the lens arrived I tried it straight away and had... the same result! All pictures are underexposed. My mobile camera (A Samsung S7 Edge) takes better photos than the D-7500 with a new Tamron lens! So, I spent $1,000 just for nothing.

Welcome! Sorry to hear about your issues. Several possibility come to mind for underexposed photos. I'm sure you probably already checked these, exposure compensation setting, and metering mode. I would probably start with a two button reset to get it back to factory, but you would think it was already done when you sent it in for service.

Hi Needa,
Yes, the camera has been re-set to factory settings multiple times. According to the Nikon repair there is nothing wrong with the camera. They took about 700 pictures.
The camera has now a picture count of 906 of which I only took 200 myself over the last eight months.

Welcome aboard. Enjoy the ride.
We look forward to seeing more posts and samples of your work.

First off, do you still have the D90 and if so, does it still work correctly with all your lenses? Second, why have you waited this long with with problem? Did you buy the camera at a camera store or mail order? If local camera store, take the camera and lenses in and insist they either make it work, exchange the camera, or take it back and give you a refund. If mail order, send them pictures from both cameras and demand they get it fixed or give you a return and refund. Also, if you have a have a local camera store, take a couple of senses with you and see if you can try them on a D7500. If the other camera works, then either your camera is defective or you are doing something wrong. See if they will help you.

I gave the D90 to my son and the quality of pictures on the D90 with the same lenses is great.
I purchased the camera at the end of June from an official Nikon camera store in Brisbane, Australia (2,200 km from Melbourne). I was in hospital for three months due to a total knee emplacement (With complications). I then addressed the problem with the Nikon camera store and they referred me to the Nikon service center in Melbourne. This has now been ongoing for two months. I still have to work as well. I spent way too much time chasing this problem and I am at the point of losing my confidence in the Nikon brand. I am at the end of my resources, hence why I signed up to this forum in the hope that somebody can give me some advice about the settings of this camera. The camera is currently at factory settings. There are so many variables and I'm by no means an expert. After spending $3,500 I just want to take acceptable pictures on automatic settings. I watched many YouTube clips but became none the wiser.
Thanks for your reply!

Trying leaving all as is and take a fixed baseline shot in good light. Increase the Exposure Comp to +1.0. Take a few shots, then move to +2.0 and take a few more. Check the images. If you don't see a pretty big difference in the results, there is something fishy going on. If, on the other hand, they are progressively more overexposed, then it may be a balance between the body and the lens. I shot a 5500 for years with Tamron lens and I had to always shoot at -.3 EC. Like yours, the body was within 'specs', but those can have quite a bit of wiggle.

A couple thoughts come to mind. By any chance do you have Auto-ISO turned on? If it's on, and if you reach the upper limit that is set in the camera, the pics can come out under exposed.

And that brings me to my second thought. Doing a factory reset only resets the shooting menu. A Nikon rep told me a factory reset doesn't reset absolutely every change that is made in the settings. Not what you want to hear though.... Keep digging in your menus.

Are we talking badly underexposed or just slightly? These lenses you have all have some amount of vignette. Try turning on the vignette control on in the camera menus to see if that helps, the zooms will likely need more help than the primes. It'd be good for you to post a few shots you are concerned about so we can see what you are talking about.